Devices for inking lithographic printing plates generally comprise a plurality of form rolls which contact a printing plate. Each of the form rolls is usually in rolling contact with one or more vibrator rollers to which ink is applied by a large number of rollers, generally twenty or more, arranged in pyramid fashion.
Inking systems currently in use generally have rollers in the ink train of varying diameters, some of which vibrate longitudinally in an effort to eliminate ghosting and to provide desired quantities of ink to the printing plate.
The quantity of ink supplied through a train of rollers to a printing plate is generally controlled by adjusting ink keys and controlling dwell time of ductor rollers to control the input of ink to the long train of rollers. Heretofore, on a press for printing sheets thirty-eight inches wide about sixty individual inker adjustments had to be correlated. Changing a first adjustment required a change of a second which in turn required a third and usually readjustment of the first. The effect of such a change was not apparent on printed sheets for about five minutes and thus resulted in wasting excessive quantities of paper, sometimes five hundred sheets or more, while the operator adjusted the ink train by trial and error.
Since ink is applied by form rollers only to image areas of the plate, form rollers have a memory because ink accumulates on areas of the form rollers which contact non-image areas of the plate. The operator is faced with the impossible task of adjusting the inker to feed ink to the areas of the form rolls corresponding to image areas while attempting to minimize accumulation on areas corresponding to non-image areas. As a result, part of the image areas are starved and undesirable accumulation results on other parts of the rollers.